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heartleaf pondweed, potamot gracieux, spotted pondweed

alga pondweed, alga-like pondweed, potamot confervoide, Tuckerman's pondweed

Rhizomes

present.

obvious.

Cauline stems

terete, conspicuously spotted, 8–95 cm;

nodal glands absent.

terete, without spots, 10–80 cm.

Turions

absent.

present, in axils of old leaves and from disintegrating branches, fusiform, 0.7–2 cm, leaves spreading to ascending.

Leaves

both submersed and floating, ± spirally arranged.

submersed, ± spirally arranged, flaccid, sessile;

stipules deliquescent, inconspicuous, convolute, free from blade, pale green, not ligulate, 0.5–1.2 cm, not fibrous, not shredding at tip, apex obtuse;

blade pale green, linear, not arcuate, 1.8–6.5 cm × 0.1–0.5 mm, base slightly tapering, without basal lobes, not clasping, margins entire, not crispate, apex not hoodlike, extremely attenuate, bristly, lacunae present, each side of midvein to margins;

veins 1.

Floating leaves

petioles continuous in color to apex, 1–16.5 cm;

blade adaxially light to dark green, lanceolate to round-ovate, 2.5–8.5 cm × 11–44 mm, base rounded to cordate, apex acute to rounded;

veins 15–21.

Submersed leaves

petiolate, lax;

stipules deliquescent, inconspicuous, convolute, free from blade, light to dark brown, not ligulate, 0.7–1.2 cm, not fibrous, not shredding at tip, apex obtuse;

petioles 0.5–4.5 cm;

blade dark green, linear-lanceolate to lanceolate, often arcuate, 3.5–13.8 cm × 60–165 mm acute, base acute to rounded, without basal lobes, margins entire, crispate, apex not hoodlike, acute to obtuse, lacunae in 2–5 rows each side of midrib;

veins 7–19.

Inflorescences

unbranched, emersed;

peduncles not dimorphic, terminal or axillary, erect to ascending, cylindric, 3.3–9.4 cm;

spikes not dimorphic, cylindric, 17–36 mm.

unbranched, emersed;

peduncles not dimorphic, terminal, ascending, somewhat clavate, (3–)5–25 cm;

spikes not dimorphic, capitate, 5–12 mm.

Fruits

sessile, dark green to dark brown, ovoid to obovoid, turgid, abaxially keeled, laterally ridged, 5–6.5 × 4.1–5 mm, lateral ridges without points;

beak erect, 0.5 mm;

embryo with 1 full spiral.

sessile, light green, round-obovoid or nearly orbicular, compressed, abaxially and laterally keeled, 2–3 × 1.7–2.8 mm, lateral keels without sharp point;

beak erect, 0.5 mm;

sides without basal tubercles;

embryo with less than 1 full spiral.

Chromosome number

apparently unknown not available.

apparently unknown not available.

Potamogeton pulcher

Potamogeton confervoides

Phenology Flowers summer–fall. Flowering early–late summer.
Habitat Stagnant to slow-flowing waters of streams, lakes, ponds, and small rivers Acidic waters of bogs, ponds, and lakes, often at higher elevation in e portion of range
Elevation 0–700 m (0–2300 ft) 0–1500 m (0–4900 ft)
Distribution
from FNA
AL; AR; CT; DE; FL; GA; IL; IN; KY; LA; MA; MD; ME; MI; MN; MO; MS; NC; NH; NJ; NY; OH; OK; PA; RI; SC; TN; TX; VA; WI; WV; NB; NS; PE; Ont
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; MA; ME; MI; NC; NH; NJ; NY; PA; RI; SC; VT; WI; NB; NL; NS; ON; QC; SPM; St Pierre
[WildflowerSearch map]
[BONAP county map]
Discussion

Potamogeton pulcher is similar in morphology to P. amplifolius and occurs in similar habitats. Potamogeton pulcher differs from P. amplifolius by the former having lanceolate to linear-lanceolate submersed leaves with fewer than 19 veins, whereas the latter has ovate submersed leaves with more than 19 veins.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Potamogeton confervoides is most uncommon and found only in fairly acidic waters. It is easily recognized by its linear, bristly leaves and the unusually long peduncle that seems out of place on a plant with such fine leaves. The leaves are so fine that they almost appear as greenish colored hair in the water. When the plant is removed from the water, the leaves are extremely flaccid leaves and essentially collapse onto each other.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 22. FNA vol. 22.
Parent taxa Potamogetonaceae > Potamogeton Potamogetonaceae > Potamogeton
Sibling taxa
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. confervoides, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. strictifolius, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
P. alpinus, P. amplifolius, P. bicupulatus, P. clystocarpus, P. crispus, P. diversifolius, P. epihydrus, P. floridanus, P. foliosus, P. friesii, P. gramineus, P. groenlandicus, P. hillii, P. illinoensis, P. natans, P. nodosus, P. oakesianus, P. oblongus, P. obtusifolius, P. ogdenii, P. perfoliatus, P. praelongus, P. pulcher, P. pusillus, P. richardsonii, P. robbinsii, P. spirillus, P. strictifolius, P. subsibiricus, P. tennesseensis, P. vaseyi, P. zosteriformis
Synonyms P. tuckermanii
Name authority Tuckerman: American Journal of Science, and Arts 45:38. (1843) Reichenbach: in H. G. L. Reichenbach et al., Icones florae germanicae et helveticae 7: 13. (1845)
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